`simple-curve`procedureBasic parametric curve constructor.

`N`- number of interpolation points (N >= 3)
`K`- continuity class of the interpolating spline for this curve (1 or 2, for first or second derivative)
`FS`- a list of one-argument procedures that are evaluated to obtain points on the curve. The length of
`FS`determines the dimensionality of the curve `TMIN`- minimum value for the curve parameter
`TMIN`- maximum value for the curve parameter